WATCH: CNN's 'debate' between Mark Cuban and Rudy Giuliani is as bonkers as you would expect
Rudy Giuliani and Mark Cuban appear on CNN (screen grab)

Just hours before Wednesday night's third presidential debate, CNN staged an undercard event between Trump surrogate Rudy Giuliani and billionaire Mark Cuban, a supporter of Hillary Clinton.

After some disagreements over the importance of Clinton's private email server, the two moved on to Trump's business experience.

"Name any of his products that are still successful," Cuban charged. "He cheated -- cheated -- 6,000 people from Trump University. Hard working men and women, he took tens of thousands of dollars from them."

"Trump games, Trump cards, Trump steaks, Trump clothes," the billionaire continued, listing Trump's failed business ventures. "When somebody has to give their name and sell their name that often, that tells me they're desperate. He has not had a long track record in business. He's done okay in real estate, but everything else, he's been a major failure at."

"Now he's crushing his brand," Cuban added. "And everything he says makes no sense because he's crushing his brand even more."

Giuliani, however, asserted that Trump "has had great success in business."

"Then why all the failures?" Cuban interrupted. "He's been sued 3,500 times, I've been sued less than 10."

Watch part 1 of the debate below.

Watch part 2 below.